Simpson, starting his round on the 10th tee, carded a 6-under score of 64. He made birdies at 13, 15, 17 and 18 to make the turn at 4 under on the long, par 70 layout. He added birdies at 1 and 2 to get to 6 under, but he lost a shot with a bogey at 3. He moved to 7 under with birdies at 6 and 7, but a bogey on 9, his final hole of the day, left him at 6 under.

Henrik Stenson is in second place alone at 5 under 65. Four players, including Tiger Woods and Keegan Bradley, are two shots behind Simpson at 4 under. Chris Wood and Ryan Moore join Woods and Bradley. Six golfers - Jason Dufner, Bubba Watson, Luke Donald, Jim Furyk, Rickie Fowler and Bill Haas - are all at 3-under 67. Scott Piercy is alone at 2 under 68.